N. Bouaricha et al., ONTOGENY OF OSMOREGULATORY STRUCTURES IN THE SHRIMP PENAEUS-JAPONICUS(CRUSTACEA, DECAPODA), The Biological bulletin, 186(1), 1994, pp. 29-40
The ontogeny of differentiated osmoregulatory epithelia in the branchi
al chamber (gills, branchiostegite, pleura, epipodite) was studied by
transmission electron microscopy throughout the postembryonic developm
ent of Penaeus japonicus. These epithelia are characterized by typical
cytological features, including apical microvilli and numerous basal
infoldings associated with mitochondria.Differentiated osmoregulatory
structures are not observed in the early larval stages: nauplii and zo
ea 1. In the next larval stages, zoeas and mysis, gills and epipodites
are developed as buds only, but osmoregulatory epithelia are observed
in the branchiostegites and pleurae. The differentiated structures of
the branchiostegites and pleurae are still present in postlarvae but
disappear in juveniles and adults. Gills and epipodites develop progre
ssively in the postlarval stages, with early differentiation of osmore
gulatory epithelia in the epipodites. In juveniles and adults, the gil
l epithelium is poorly differentiated; in contrast, abundant different
iated osmoregulatory structures are observed in the epipodites. Ontoge
netical comparisons of these observations with previous studies in the
same species reveal strong correlations between the development of os
moregulatory epithelia, the ability to osmoregulate, the activity of N
a+-K+ ATPase, and salinity tolerance during the postembryonic developm
ent of Penaeus japonicus.